Tubular radiator



Aug. 29, 1939. G W DAY 2,171,253

` TUBULAR RADIATOR Filed OC.. 22, 1958 Snventor am @ma Bg l y z /f f f I Gttornegs with cooperating the tube sections `plates of less expensive ferrous metal.

Patented Aug. 29, 1939 UNITED STATES PATENT OFFICE TUBULAR RADIATOR George W. Day, Newfane, N. Y., assignor to General Motors Corporation,

poration of Delaware Detroit, Mich., a cor- Application October 22, 1938, Seriall No.v 236,401

4 Claims.

tubular sections nested one within the otherv in succession, with succeeding sections provided seating formations to constitute locating pockets for the reception of the n plates, whereby the parts are interiitted and maintained in assembled relation.

An object of the invention is to provide an eiiicient and rugged-construction for manufacture at low cost. The tube sections and n plates can be produced without complicated and precision equipment and their assembly involves only the simple expedient of nesting the parts in ordered arrangement for any size core desired. Furthermore, the gage of the metal or wall thickness can vary within relatively wide limits and close tolerances need not be followed in the selection of raw stock. In addition, the metals selected for the fin plates can be diierent from that of the tube sections. The choice of metals will be dependent upon the type of installation and in the case of an automobile radiator, for example,

preferably would be. of a corrosion resistant metal, such as copper, and the n Because of the nested arrangement, the tube is of double wall thickness and the two ply strength makes the structure especially adapted for fluid pressure systems. It also enables the use of lighter gage material than is ordinarily required for equivalent pressure resistant tubing and the lighter gage material is easier to work and form to desired shape.

For a better understanding of the invention reference may be made to the accompanying drawing wherein Figure 1 is an elevation of a heat exchanger of one type to which the invention is applicable; Figure 2 is an enlarged sectional view of a portion of the exchanger assembly; Figure 3 is a sectional View showing a view of the partsprior to assembly and Figures 4 and 5 are perspective views of 'tube sections, one being of circular outline and the other oblong.

As applied to an automobile radiator asI a typical example of a heat exchange device, the parts will be assembled `as a core I comprising a series of spaced tubes or conduits connecting upper and lower headers 2 and 3, with heat radiating ins dividing the spaceA into a number of small air cells. Each conduit consists of a stack of nested tube sections and the iin plates are located in proper spaced relation by being held between suitable seats on succeeding tube sections.

The individual 'tube sections, according to the preferred embodiment, consist essentially of a small diameter portion 4 and a large diameter portion 5 joined together by an offset portion or shoulder 6 with the enlarged portion 5 terminating in an outwardly flaring ange 1. The formation of this part may be accomplished in any convenient fashion'as, for example, by cutting tube stock of selected diameter to given length and then expanding or drawing one end to form the enlarged portion 5 having an internal diameter substantially corresponding to the outside diameter of the opposite and unworked end portion 4. In the forming operation the oiset portion 6 will result and the rim 1 can be turned out at the same time. Both the portions 6 and 1 are illustrated as being of frustoconical shape because this is convenient to form and additionally provides a tapered surface for an interlocking joint.

Because the outside diameter of the smaller portion 4 is substantially the same as the internal diameter of the enlarged portion 5 a group of the tube sections can be brought into axial alignment and nested within or sleeved one on the other to constitute a double wall tube. In otherwords, the reduced portion 4 of one tube section can be fitted i-nto the enlarged portion 5 of the next succeeding tube section, while its enlarged portion 5 in turn is sleeved on thereduced portion 4 of the next succeeding tube section on the other side. When the tube sections are thus assembled the frusto-conical offset 6 of one tube section is brought into cooperating relation with the frusto-conical ilange I of the next section and provides an annular seating pocket for an associated fin plate.

The completed tube extends through a series of iin plates 8 each having openings at suitable intervals to receive the several tubes." 'At each opening, the rim or marginal portion is bent away or tapered to form a frusto-conical flange 9 to lit in the tube pocket between thecooperating shoulder 6 and ilange lof succeeding tube sections. This affords an effective interlocking connection between the parts and locates th'en plates in proper spaced relation to one another. To bond the parts and seal the joints, the several tube sections may be pre-tinned and the whole assembly subjected to a brazing temperature after assembly.

While the drawing shows the several fin plates between the cooperating seats of succeeding sections. In any event, each tube section engages a n plate intermediate its ends and has its small diameter tube portion 4 projecting through the central aperture and beyond one side of the fin 8 and its large diameter tube portion 5 projecting on the opposite side of the n. In assembling the core, the tube sections and fins are stacked alternately one on top of the other until the desired over-all size is reached. In the case of the endmost tube sections a' special half length section,

as shown at I0, may be provided to hold in place.

the endmost fin plate and the endmost n plate in this instance can be utilized as the bottom Wall of the header tank. For joining the end plate to the header tank 2 an inturned marginal flange I I may be provided on the tank wall to engage the underside of the endmost plate, and the abutting surfaces brazed or otherwise joined together. It should be noted incidentally that the cross sectional shape of the tube sections may be round as seen in Figure 4 or oblong as in Figure 5 or any other appropriate hollow sectional shape.

I claim: n

1. In a. heat exchanger, a series of spaced fins having aligned apertures with frusta-conical rims, and a series of nested tube sections projecting through said apertures with succeeding tube-,sections provided with cooperating frustoconical portions engaging opposite sides of said rusto-conical rims;

2. In a heat exchanger, a series of spaced n plates having aligned openings therein, a series of tubes, each projecting through a plate opening and having an intermediate offset engaging the rim of said opening and opposite end portions extending on opposite sides of said plate for nested engagement with next adjacent tubes with one of said end portions cooperating with the intermediate portion ofan adjacent tube to provide a retaining pocket for the plate rim.

3. In a heat exchanger, a series of tube sections arranged in axial succession and each having an intermediate shoulder with the portion on one side of the shoulder of larger diameter than that on the other side, and said larger diameter portion being sleeved on the smaller diameter portion of the next succeeding tube section and terminating in spaced relation to the shoulder thereof for cooperation therewith in affording an annular pocket, and a series of ns having apertures through which the tubes project with the rim portions about theiapertures seated in said annular pockets.

4. In a heat exchanger, a series of spaced n plates having aligned openings therethrough, and a conduit projecting through said openings and comprising a series of nested tubes, each having a portion intermediate its ends bearing on a l n plate with its opposite end portions extending beyond opposite sides, respectively, of said plate and fitting complementary portions of next adjoining tubes.

GEORGE W. DAY. 

